It is surprising that 2020 TurboTax didn't report your Excess Contribution. You should Amend your 2020 return and go through that section again.
You are correct that once the excess is known in 2020, there are several ways to handle it, including rolling it over to 2021.
However, If you report the excess in 2021 (for 2020), you will be charged the penalty for 2021 if you don't remove it before tax filing deadline. TurboTax would not know that you didn't pay it in 2020; it is only calculating for 2021.
Click this link for detailed info on reporting Excess Contributions and how to handle them.
**Say "Thanks" by clicking the thumb icon in a post
**Mark the post that answers your question by clicking on "Mark as Best Answer"
